Influence of pain score measured by a visual analog scale (PS-VAS) on the Health Assessment Questionnaire Disability Index and 28-joint Disease Activity Index with C-reactive protein in rheumatoid arthritis patients.

BACKGROUND: Pain is a serious burden for rheumatoid arthritis (RA) patients. However, the effect on Health Assessment Questionnaire Disability Index (HAQ-DI) and 28-joint Disease Activity Score (DAS28) has not been presented. The aim of this study is to evaluate them in a case series. METHODS: Three hundred and eighty-two RA patients who were treated for more than 5 years were studied. The parameters assessed included average value of the DAS28 with C-reactive protein (DAS28-CRP), the HAQ-DI score, the Sharp/van der Heijde Score (SvdHS), age, and the pain score measured by a visual analog scale (PS-VAS). Relationships among these factors and the relationships between the HAQ-DI score and the other factors, and the relationships between the change in HAQ-DI scores and the changes in other factors were evaluated statistically with multivariate linear regression analysis. The effect of PS-VAS on HAQ-DI was compared with that of DAS28-CRP on the overlapping data of each parameter. RESULTS: HAQ-DI demonstrated significant positive correlations with all parameters. However, PS-VAS demonstrated a stronger effect than DAS28-CRP, also demonstrated without overlapping data. After minimizing the effects of DAS28-CRP, age and SvdHS, there was a significant correlation between HAQ-DI and PS-VAS in all analyses. The change in HAQ-DI demonstrated a significant correlation with the change in PS-VAS. CONCLUSIONS: These results suggested that HAQ-DI is deeply influenced by PS-VAS. The effect of DAS28-CRP overlapped with the effect of PS-VAS in a major way. Pain control for RA patients is the most important factor contributing to activities of daily living, as well as disease activity control.

Lymphocyte opioid receptors as innovative biomarkers of osteoarthritic pain, for the assessment and risk management of opioid tailored therapy, before hip surgery, to prevent chronic pain and opioid tolerance/addiction development: OpMarkArt (Opioids-Markers-Arthroprosthesis) study protocol for a randomized controlled trial.

BACKGROUND: The incidence of post-surgical chronic pain ranges between 20% and 40% in Europe. Osteoarthritis pain after prosthesis implantation is one of the most severe secondary syndromes, depending not only on surgery but also on organic changes before and after joints replacement. No data are available about risk factors. An excessive inflammatory response plays a central role but a best therapy is not defined yet. It is not clear whether opioid administration could influence post-surgical pain and lead to tolerance or addiction. Interestingly, the immune system, together with the nervous and peptidergic ones, is involved in hypersensibility. The connection across the three biological systems lies in the presence of opioid receptors on immune cells surface. Here, we show a method to analyze whether opioids could modulate lymphocytes, by proposing opioid receptors as biological markers to prevent chronic pain and opioid tolerance or addiction after hip surgery. METHODS/DESIGN: After institutional independent ethics committee approval, 60 patients, in pain and undergoing hip surgery, will be enrolled in a single-blind, randomized, phase IV, pilot study. Pain treatment will be selected inside a class of non-steroidal anti-inflammatory drugs (NAISDs) or paracetamol or a class of opioids, into three medication arms: 25 mg tapentadol twice daily; 75 mg tapentadol twice daily; NSAIDs or paracetamol in accordance with surgeon's custom. For each group, we will collect blood samples before, during and after surgery, to apply molecular analysis. We will perform lymphocyte opioid receptors genes and proteins expression and functional analysis. Data will be statistically analyzed. DISCUSSION: This project has the potential to obtain a personalized diagnostic kit, by considering lymphocyte opioid receptors as biological markers. Starting from a simple blood sample, it will be possible to decide the best therapy for a single patient. Using a noninvasive approach, we expect to fix a daily standard dose and timing, before and after surgery, to bypass hip chronic pain and the insurgence of tolerance or addiction. The analysis of opioid receptors sensitivity will help to identify the best drug administration in each specific case (tailored therapy). TRIAL REGISTRATION: ISRCTN, ISRCTN12559751 . Retrospectively registered on 23 May 2017.